1. Field of the Invention
This invention relates to facing materials such as ceramic tiles which are installed over substrates such as floors, ceilings and walls using a support plate or decoupling mat between the substrate and the facing material to minimize or eliminate stresses which may cause cracking or detachment of the facing material from the substrate.
2. Description of Related Art
The use of facing materials, such as, ceramic tiles are well known to provide an aesthetically pleasing appearance as well as durability and wear resistance. The following description will be directed to ceramic tiles for convenience although it should be appreciated by those skilled in the art that other facing materials such as stone flooring, granite, slate, plastics, and the like, may be employed with the support plate of the invention.
In general, ceramic tile is installed over a substrate such as a wooden floor using a mortar to set the tile. Unfortunately, because of the differences in properties between the substrate, mortar, and ceramic tile, stresses formed during such installation often result in damage in the form of cracks or delamination. Previously, most ceramic tile installations utilized mud setting beds, wherein a mixture of sand and cement was applied over the floor or other substrate and the ceramic tile set in the mud. The mud beds were generally in the range of about 1½ inch thick.
Modem ceramic tile installations now often use thin layer processes, which require use of thin-set mortar systems wherein the thickness of the thin-set mortar is about ½ inch thick. Flooring systems of this type are generally less costly, lighter, and more easily coordinated with installations of ceramic tile and stone.
Because of the thinness of the installation however, stresses at the interface between the mortar, substrate, and ceramic tile are much greater than in the case of a thin bed installation and it has been found that these stresses cause cracking of the tile and/or delamination of the tile of the floor. In an effort to decrease the stress differences and the problems of tile cracking and delamination, support plates or otherwise known as decoupling or uncoupling plates/mats have been developed. Currently available support plates are used between the substrate and the ceramic or stone tile to provide a base for the tile, as well as to decrease or eliminate the stresses in the installation. A number of support plates have been developed as indicated in the following patents.
U.S. Pat. No. 4,917,933 discloses a plastic sheet that is used as a sub-carrier and provides a series of parallel, alternating, dovetailed-shaped channels and grooves. A cross-meshed lattice matting, having filaments, is glued or partially fused to the backside of the plastic sheet and serves to anchor the sheet to the underlying foundation.
In U.S. Pat. No. 5,255,482 a support plate is used between a rigid horizontal base and a top flooring layer (i.e., tile). The support plate is a crack isolation layer that comprises a hard, essentially rigid material, that is in load bearing relationship with the base and the top flooring layer. The crack isolation layer comprises precast rigid crack isolation sheets having recesses or holes. Alternatively, the crack isolation layer comprises a plurality of spaced pilings of rigid, non-compressible material, which are mounted in spaced apart relationship on a cloth matting.
U.S. Pat. No. 6,434,901 shows another support plate of a sheet material having a number of recesses therein. Each recess within this support plate has overhangs that define undercut portions therein that entrap mortar in the recess and provide a secure bond between a ceramic tile and the support plate. The support plate is positioned on the substrate and secured thereto, and then thin-set mortar is applied to the surface of the support plate and fills the recesses within such plate.
In UK Patent Application GB 2141459 a drainage plate is shown having stamped-out portions recessed on one side of the plate with u-shaped openings provided in the inclined laterals walls of the these recessed portions to permit water to pass there-through. The drainage plate is installed between the substrate and the ceramic tile.
In U.S. Pat. No. 7,536,835 a support plate having support elements that are hollow towards the underside, capable of support, and project out beyond the top of the support plate, is applied on the sub-floor. Channels carrying open water are formed between the support elements and a water-permeable covering that is disposed on the support elements. The support plate is embedded in a thin-bed mortar layer on the sub floor, and ceramic tiles are laid and attached to a covering (non-woven fabric) residing on the other side of the support plate.
In U.S. Publication Application No. US/200610201092, another support plate is shown for achieving a coupling between the base and a surface cladding. This support plate has multiple open chambers with a net-like fabric attached at the open end of such chamber. A thin-set mortar is applied over the support plate to fill the chambers and secure the mortar to the plate via the net-like fabric for attaching the support plate to the ceramic tile.
Unfortunately, while the prior art has developed a number of support plates to be used in ceramic and stone tile installations, each of these prior art support plates continues to introduce some level or degree of unwanted stress cracking and/or delamination. As such, there is still a need for improved support plates that decrease and/or avoid stress cracking of the tiles, while also decreasing and/or avoiding delamination of the tiles caused by stresses resulting in the installation.